Some thoughts I've had:
As you've said, soil, or other mediums will compress.
There are a few barriers to get over in the design. In a hydro setup, the container will need a lid, with a small cutout for the stem, and a watertight and strong seal around the outer edge. As centrifugal force pushes the water outwards. If the container is full, you'll end up with a small 'cone' or 'vortex' around the base of the stem with an absence of water, but as long as the roots are covered, you'll be fine there.
The air pump connection would require a perfectly centered inlet at the bottom of the pot, and you'll need a high quality swivel fitting. Under the speeds and torque of a centrifuge, I would imagine you'll need a fitting with bearings, and considering this plans to be used to grow medical Cannabis, a food grade grease should be used in those bearings.
You'll need a remotely operated valve to drain the container if done while spinning (no wires), or you can take the design of an automobile horn in a steering wheel, using that spring loaded horn wire to keep a constant connection while the wheel is turned, holding pressure between 1 stationary conductive plate, and 1 conductive plate that's in motion.
A stationary top fill hose will work, providing the plant is centered in the pot. The more off center the plant is, the larger the hole needs to be cut.
Does your plan involve a stationary reservoir with the plant, basket, roots, etc.. turning within the reservoir, or will the plant, basket, roots, and reservoir all be spinning as one?